They are definitely not compatible, at least judging by outside appearance. The old insert is most often reusable (can be unscrewed from the old bit of hose). I’ve never heard of reusing an olive, they compress when installed and can’t be removed non-destructively.
They can be removed .. you just cut away the hose after removing the barb.. whether they still seal well is another matter as is getting them onto the remaining hose (it will wear off some of the outer) and to some extent depends how crushed up they were for the first tighten…
From experience the recommended torque is somewhere in the mid point… the olive still has some life left… but its an obvious YMMV… and obviously you may die …
I no longer have my SRAM but with Shimano I have managed to change cables over from the factory torque… then compress just a bit more next time.. stick some dry paper towel in the hood/cover and inspect regularly for signs of leaking.. (Not sure how that works with DOT but with mineral oil it’s apparent if there is any leakage into a dry shop towel)
At least the existing olive it the right shape…if you can get it over the hose. The shimano olive is a different shape.
I’ve reused an olive .. for a weekend… then got home and the SRAM Olive and barb arrived… so whipped it off and put on the new one.. However each time you do this you lose a bit more hose…
I’d wonder about DOT5.1 having issues with Shimano olives and barbs
No both are metal …